But after an excellent start to his second season under Louis van Gaal, Shaw's progress was derailed when he suffered a double break of his right leg against PSV Eindhoven in September.

It is believed concerns over that right leg prompted Shaw to withdraw himself from that game against Swansea.

Shaw's continued absence since has been a source of puzzlement for many United fans but Mourinho insists he must keep fighting to prove he deserves to start.

"The only thing I can say is that Luke is working well," Mourinho said. "He doesn't have any problem and he is working well. He is fighting hard. There is no problem with him. He is fighting hard."

United's upcoming congested fixture list could work in Shaw's favour as they continue to battle in four competitions.

St Etienne travel to Old Trafford on Thursday in the last 32 of the Europa League in the first of four games in 11 days for United.

United travel to Blackburn in the FA Cup on Sunday, before heading to France on February 22 for the return leg against St Etienne and they then play Southampton in the EFL Cup final at Wembley on February 26.